ORIGINAL RESEARCH
A Megacity-Scale Analysis of Sludge Management
and Carbon Footprint in China
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1
Shanghai Urban Construction Design & Research Institute Groups Co., Ltd., 3447 Dongfang Rd, Shanghai PR China
2
College of Environmental Science & Engineering, Tongji University, Shanghai PR China
3
Yangtze Eco-Environment Engineering Research Center, China Three Gorges Corporation, Shanghai PR China
4
Shanghai Urban Stormwater Management Engineering & Technology Research Center, Shanghai PR China
Submission date: 2021-07-14
Final revision date: 2021-10-19
Acceptance date: 2021-10-31
Online publication date: 2022-02-14
Publication date: 2022-04-06
Corresponding author
Jianguo Tang
Shanghai Urban Construction Design & Research Institute Groups Co., Ltd., China
Pol. J. Environ. Stud. 2022;31(3):2451-2460
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ABSTRACT
With the growing capacity of wastewater treated, a large amount of sludge has been generated
in China. Shanghai has 42 wastewater treatment plants (WWTPs), with a total design capacity
of 8.5×106 m3/day. The sludge production per Capita is higher than in other Chinese regions.
The sludge management strategy has changed drastically over the past three years in Shanghai.
As to the sludge treatment, deep dewatering technologies such as filter-press dewatering and vacuum
filter-press dewatering are the most used methods. On the other hand, the ratio of sludge anaerobic
digestion and aerobic composting is very low due to the poor sludge quality. Regarding sludge
disposal, sludge landfill has been phasing out, but the ratio of sludge incineration has increased
significantly. The carbon footprint results show landfill alternatives generally have more greenhouse
gas (GHG) emissions than sludge incineration and land use alternatives. The average CO2 per ton dry
solids (DS) has reduced from 0.91 in 2019 to 0.67 ton CO2/t DS in 2020 thanks to the optimization
of sludge disposal. This study suggests deep dewatering treatment followed by incineration is considered
the reasonable and sustainable sludge management scenario in a megacity.